A cluster of tapeworm eggs discovered in 270-million-year-old fossilized shark feces suggests that intestinal parasites in vertebrates are much older than previously known, according to research published January 30 in the open access journal PLOS ONE by Paula Dentzien-Dias and colleagues from the Federal University of Rio Grande, Brazil.

Remains of such parasites in vertebrates from this era are rare- of 500 samples examined, only one revealed the tapeworm eggs. This particular discovery helps establish a timeline for the evolution of present-day parasitic tapeworms that occur in foods like pork, fish and beef. The fossilized eggs were found in a cluster very similar to those laid by modern tapeworms. Some of them are un-hatched and one contains what appears to be a developing larva. According to the study, "This discovery shows that the fossil record of vertebrate intestinal parasites is much older than was previously known and occurred at least 270-300 million years ago."

Wednesday, January 30, 2013

South Korea launched its first space rocket carrying a science satellite on Wednesday amid heightened regional tensions, caused in part, by North Korea’s successful launch of its own rocket last month.

It was South Korea’s third attempt to launch a civilian rocket to send a satellite in orbit in the past four years and came after two previous launches were aborted at the eleventh hour last year due to technical glitches.

The launch vehicle, named Naro, lifted off from South Korea’s space center on the south coast and successfully went through stage separation before entering orbit, officials at the mission control said. Previous launches failed within minutes.

Although viviparity (live birth) has evolved from oviparity (egg laying) at least 140 times in vertebrates, nearly 120 of these independent events occurred within a single reptile taxon. Surprisingly, only squamate reptiles (lizards and snakes) are capable of facilitating embryonic development to increasingly advanced stages inside the mother during extended periods of oviducal egg retention. Viviparity has never evolved in turtle lineages, presumably because embryos enter and remain in an arrested state until after eggs are laid, regardless of the duration of egg retention. Until now, the limiting factor that initiates and maintains developmental arrest has remained elusive. Here, we show that oviducal hypoxia arrests embryonic development. We demonstrate that hypoxia can maintain developmental arrest after oviposition and that subsequent exposure of arrested embryos to normoxia triggers resumption of their development. We discovered remarkably low oxygen partial pressure in the oviducts of gravid turtles and found that secretions produced by the oviduct retard oxygen diffusion. Our results suggest that an extremely hypoxic environment in the oviduct arrests embryonic development and may constrain the evolution of viviparity in turtles, with the reduced diffusive capacity of oviducal secretions possibly creating or contributing to this hypoxia. We anticipate that these findings will allow us to better understand the mechanisms underlying the evolutionary transition between reproductive modes.

Chinese coal consumption surged for a 12th consecutive year in 2011, with the country burning 2.3 billion tons of the carbon-emitting mineral to run power plants, industrial boilers and other equipment to support its economic and population growth.

In a simple but striking chart published on its website, the U.S. Energy Information Administration plotted China's progress as the world's dominant coal-consuming country, shooting past rival economies like the United States, India and Russia as well as regional powers such as Japan and South Korea.

In fact, according to EIA, the 325-million-ton increase in Chinese coal consumption in 2011 accounted for 87 percent of the entire world's growth for the year, which was estimated at 374 million tons. Since 2000, China has accounted for 82 percent of the world's coal demand growth, with a 2.3-billion-ton surge, the agency said.

"China now accounts for 47 percent of global coal consumption -- almost as much as the rest of the world combined," EIA said of the latest figures.

The rising consumption numbers reflect a 200-plus percent increase in Chinese electricity generation since 2000, with most of the new power coming from coal-fired power plants. Chinese growth averaged 9 percent per year from 2000 to 2010, more than twice the 4 percent global growth rate for coal consumption. And when China is excluded from the tally, growth in coal use averaged only 1 percent for the rest of the world over the 2000-2010 period, according to EIA.

Tuesday, January 29, 2013

before construction via google maps, after site clearing on google maps and a flyover from someone's plane in the beginning of January. The building's name is Computational Research and Theory. That's right, CRT. Oy. We couldn't get a cool name like the Helios Building (solar power research) or the Molecular Foundry (nanotech). We got CRT. Thanks, Chu!

At least it'll be a monster of a computer room and be energy efficient. Still gonna be fugly though.

Whether introduced species invasions pose a major threat to biodiversity is hotly debated. Much of this debate is fueled by recent findings that competition from introduced organisms has driven remarkably few plant species to extinction. Instead, native plant species in invaded ecosystems are often found in refugia: patchy, marginal habitats unsuitable to their nonnative competitors. However, whether the colonization and extinction dynamics of these refugia allow long-term native persistence is uncertain. Of particular concern is the possibility that invasive plants may induce an extinction debt in the native flora, where persistence over the short term masks deterministic extinction trajectories. We examined how invader impacts on landscape structure influence native plant persistence by combining recently developed quantitative techniques for evaluating metapopulation persistence with field measurements of an invaded plant community. We found that European grass invasion of an edaphically heterogeneous California landscape has greatly decreased the likelihood of the persistence of native metapopulations. It does so via two main pathways: (i) decreasing the size of native refugia, which reduces seed production and increases local extinction, and (ii) eroding the dispersal permeability of the matrix between refugia, which reduces their connectivity. Even when native plant extinction is the deterministic outcome of invasion, the time to extinction can be on the order of hundreds of years. We conclude that the relatively short time since invasion in many parts of the world is insufficient to observe the full impact of plant invasions on native biodiversity.

Valley-filling deposits of the Nama Group, southern Namibia, record two episodes of erosional downcutting and backfill, developed close together in time near the Ediacaran-Cambrian boundary. Geochronological constraints indicate that the older valley fill began 539.4 ± 1 Ma or later; the younger of these deposits contains unusually well-preserved populations of the basal Cambrian trace fossil Treptichnus pedum. Facies analysis shows that T. pedum is closely linked to a nearshore sandstone deposit, indicating a close environmental or taphonomic connection to very shallow, mud-draped sandy seafloor swept by tidal currents. Facies restriction may limit the biostratigraphic potential of T. pedum in Namibia and elsewhere, but it also illuminates functional and ecological interpretation. The T. pedum tracemaker was a motile bilaterian animal that lived below the sediment-water interface—propelling itself forward in upward-curving projections that breached the sediment surface. The T. pedum animal, therefore, lived infaunally, perhaps to avoid predation, surfacing regularly to feed and take in oxygen. Alternatively, the T. pedum animal may have been a deposit feeder that surfaced largely for purposes of gas exchange, an interpretation that has some support in the observed association of T. pedum with mud drapes. Treptichnus pedum provides our oldest record of animals that combined anatomical and behavioral complexity. Insights from comparative biology suggest that basal Cambrian T. pedum animals already possessed the anatomical, neurological, and genetic complexity needed to enable the body plan and behavioral diversification recorded by younger Cambrian fossils.

This is an old paper, but one that is not on their 'horizon' for the nonspecialists.

Iran said on Monday it had launched a live monkey into space, seeking to show off missile delivery systems that are alarming to the West given Tehran’s parallel advances in nuclear technology.

The defence ministry announced the launch as world powers sought to agree a date and venue with Iran for resuming talks to resolve a nuclear standoff with the West before it degenerates into a new Middle East war.

Efforts to nail down a new meeting have failed repeatedly and the powers fear Iran is exploiting the diplomatic vacuum to hone the means to produce nuclear weapons.

The Islamic Republic denies seeking weapons capability and says it seeks only electricity from its uranium enrichment so it can export more of its oil wealth.

The powers have proposed new talks in February, a spokesman for the European Union’s foreign policy chief said on Monday, hours after Russia urged all concerned to “stop behaving like children” and commit to a meeting.

Iran earlier in the day denied media reports of a major explosion at one of its most sensitive, underground enrichment plants, describing them as Western propaganda designed to influence the nuclear talks.

An defence ministry said the space launch of the monkey coincided “with the days of” the Prophet Mohammad’s birthday, which was last week, but gave no date, according to a statement carried by the official news agency IRNA.

The launch was “another giant step” in space technology and biological research “which is the monopoly of a few countries,” the statement said.

The monkey was sent up in a Kavoshgar rocket dubbed “Pishgam” (Pioneer), reaching a height of more than 120 km (75 miles), IRNA said.

CEO Jim McKenzie said China has dominated the rare-earth elements market, and the Alaska project gives the U.S. a chance to keep up. Rare-earth elements are the types of elements used in technology such as radar systems, satellites, renewable energy systems and consumer products like cell phones and TVs.

"We view the rare-earth space as sort of a race," McKenzie said. "Obviously, China is withdrawing product from international markets fairly aggressively, and the U.S. needs this product."

The company estimates that building a mine and processing facility would cost about $221 million and take about 21 months to complete. Based on curr ent resource estimates, the mine could operate for 11 years with a processing rate of 1,500 tons per day.

Abundant calcareous tubeworms have been found in both shallow platform and deep basin deposits after the end-Permian mass extinction in the Cili area, South China. Tubeworms from the microbialites deposited on the shallow platform appear to be cone-shaped tubes with diameters ranging from 0.5 to 1.8 mm (mean 1.1 mm), while those attached to Claraia, the most abundant bivalve fossil preserved in the deep basin deposits after the mass extinction, are planispiral tubes with smaller diameters (0.5–1.5 mm, mean 0.9 mm). The calcareous tubeworms are identified as Microconchida (Tentaculita) according to the typical laminated sheet texture of the tubeworms found on the shallow platform. The difference in morphology between the cone-shaped tubeworms found in the microbialites and the planispiral tubeworms attached to Claraia in deeper water deposits may be related to differences in how fast the surrounding sediments were accumulating. Bacterially mediated precipitation of calcium carbonate led to rapid accumulation of the microbialites that forced the tubeworms to grow upward so as to keep up with the rate of microbialite growth and led to the cone-shaped tubes found there, whereas the slowly accumulating sediments surrounding the tubeworm-encrusted Claraia led to the development of the planispiral forms in basin deposits. Calcareous tubeworms found in the shallow platform and colonizing the shells of bivalve Claraia in basin deposits indicates calcareous tubeworms, as a significant disaster form, should have benefited from the opening of ecological space by the extinction of most marine invertebrates. Widespread oceanic anoxia has long been considered to be one of the extraordinary conditions after the end-Permian mass extinction. Tubeworm fossils flourishing in basin deposits within the short interval near the Permian-Triassic boundary implies that the deepwater environment immediately after the end-Permian mass extinction may not have been as anoxic as previously thought.

This is not a new paper, but one I recently found and thought I'd highlight.

The proton is the primary building block of the visible Universe, but many of its properties—such as its charge radius and its anomalous magnetic moment—are not well understood. The root-mean-square charge radius, rp, has been determined with an accuracy of 2 per cent (at best) by electron–proton scattering experiments1, 2. The present most accurate value of rp (with an uncertainty of 1 per cent) is given by the CODATA compilation of physical constants3. This value is based mainly on precision spectroscopy of atomic hydrogen4, 5, 6, 7 and calculations of bound-state quantum electrodynamics (QED; refs 8, 9). The accuracy of rp as deduced from electron–proton scattering limits the testing of bound-state QED in atomic hydrogen as well as the determination of the Rydberg constant (currently the most accurately measured fundamental physical constant3). An attractive means to improve the accuracy in the measurement of rp is provided by muonic hydrogen (a proton orbited by a negative muon); its much smaller Bohr radius compared to ordinary atomic hydrogen causes enhancement of effects related to the finite size of the proton. In particular, the Lamb shift10 (the energy difference between the 2S1/2 and 2P1/2 states) is affected by as much as 2 per cent. Here we use pulsed laser spectroscopy to measure a muonic Lamb shift of 49,881.88(76) GHz. On the basis of present calculations11, 12, 13, 14, 15 of fine and hyperfine splittings and QED terms, we find rp = 0.84184(67) fm, which differs by 5.0 standard deviations from the CODATA value3 of 0.8768(69) fm. Our result implies that either the Rydberg constant has to be shifted by −110 kHz/c (4.9 standard deviations), or the calculations of the QED effects in atomic hydrogen or muonic hydrogen atoms are insufficient.

A few bits.

First, its smaller than it ought to be using this experimental method (~4%).

Second, they do not know the source of the oddness.

Third, please keep in mind what happened with OPERA and the FTL neutrinos that it was supposedly producing. This may also be a side effect of something obvious and stupid.

g. Department of Mineralogy and Petrology, University of Miskolc, Miskolc, Hungary

*. Corresponding author, Email: p.wignall@see.leeds.ac.uk

Abstract:

The Capitanian (middle Permian) extinction and recovery event is examined in carbonate platform settings from western Tethys (Hungary and Hydra, Greece). The age model for these sections is poorly resolved and we have constructed a δ13C chemostratigraphic correlation scheme, supported by conodont and foraminifer data, which attempts correlation with the well-dated events in China. This reveals the timing of events was similar in all Tethyan regions: extinction losses in the middle of the Capitanian produced late Capitanian assemblages in Hungary and Hydra with a distinctive late Permian character (for example, they lack large fusulinaceans). There is no evidence for an extinction event at the end of the Guadalupian (Capitanian) suggesting that previous claims for an end-Guadalupian mass extinction are based on poorly dated records of a mid-Capitanian event. Base level was stable through much of the middle–late Permian transition with the exception of a major regression within the Capitanian Stage. The subsequent transgression established widespread shallow-water carbonate deposition, such as the Episkopi Formation in Hydra and the Nagyvisnyó Limestone Formation in Hungary.

Missed this one a while back. Timing is damned important here for this sort of thing. The Guadalupean was a smaller mass extinction but an important one: the dinocephalians probably bit it then.

Numerous coprolites have been found in the Vyazniki and Gorokhovets localities of European Russia. Five identified coprolite-bearing horizons occur in the upper Permian deposits of the Vyatkian Regional Stage. Coprolites were collected from mudstone with a coprolite breccia-like layer and also from intraformational conglomerates that were deposited in a floodplain and overbank environment. Two coprolite morphotypes (A and B) are recognized from size and shape analysis of 32 specimens. Morphotype A has long, nonsegmented feces. Smaller, cylindrical or tubular-shaped coprolites of morphotype B are commonly segmented. SEM images of the coprolite matrix show spheres and thinwalled vesicles with diameters 0.5–4 μm. Electron Micro Probe (EMP) analyses of polished thin sections show microcrystalline carbonate-fluoride-bearing calcium phosphate with small amounts of calcium replaced in the crystal lattice. Optical microscopy and EMP investigations show that iron and manganese oxides are responsible for elevated iron and manganese concentrations in the bulk mass of coprolites. Other metals (V, Ni) can be associated with oxides forming spheroids with diameters 3–10 μm. REEs (rare earth elements, U, and other trace element concentrations suggest significant eolian sediment input to the burial environment of the coprolites. The scats contain fish scales and bones of tetrapods (amphibians or reptiles). In one large-sized coprolite, a small fragment of therapsid bone was also found. Both morphotypes are matched to carnivorous taxa within the Archosaurus rossicus zone of the Eastern Europe. The size and shape of the best-preserved specimens suggest that they were possibly produced by a large therapsid, anthracosaur, or early archosauromorph predator.

How constrained is the fossil? I've seen differing ages of between 120 to 140 million years old. That's quite a range.

The press release is pretty bad. I think that's pretty obvious now that feathers evolved as either for insulation or display first (or both) and then were adapted to flight. The research seems overwhelming at this point.

Geologists and palaeontologists have expressed mixed views about the effects of the end-Permian mass extinction on continental habitats and on terrestrial life. Current work suggests that the effects on land were substantial, with massive erosion following the stripping of vegetation, associated with long-term aridification and short-term bursts of warming and acid rain. Wildfires at the Permo-Triassic boundary contributed to the removal of forests and the prolonged absence of forests from the Earth's surface for up to 10 Myr. These physical crises on land impinged on the oceans, suggesting tight interlocking of terrestrial and marine crises. Levels of extinction on land may well have been as high as in the sea, and this is certainly the case for tetrapods. The mass extinction seems to have been less profound for plants and insects, but it is hard at present to disentangle issues of data quality from reductions in abundance and diversity. Several killing agents have been proposed, and of these tetrapods may have succumbed primarily to acid rain, mass wasting, and aridification. Plants may have been more affected by the sudden effects of heating and wildfires, and the crisis for insects has yet to be explored.

A recently excavated locality in the Chemnitz Petrified Forest, lower Permian in age and occurring within the Leukersdorf Formation of the Chemnitz Basin, Germany, provides evidence for an outstanding fossil assemblage buried in situ by pyroclastics. The environment is interpreted as forested lowland that sheltered a dense hygrophilous vegetation of ferns, sphenophytes, and gymnosperms, as well as a diverse fauna of reptiles, amphibians, arthropods, and gastropods. A detailed measured section of the outcrop documents the early volcanic history of the Chemnitz fossil forest, including a paleosol that shows the root systems of Psaronius tree ferns, Arthropitys calamitaleans, and Medullosa and Cordaixylon gymnosperms in the same horizon. Fifty-three trunks are still standing upright and rooted at their place of growth, providing evidence that the top of the paleosol was the land surface on which the forest grew, thereby offering insights into the original plant community structure and density. Taphonomic analysis of both the petrified and adpression-fossil assemblages enable us to reconstruct the direction, estimate the violence and extent of the volcanic events, and their effects on the entire ecosystem. A complete dataset of three-dimensional coordinates resulting from three and one-half years of continuing excavation and study permits the recognition of organ connections and results in the first reconstructions of the excavation site, the floral elements, and the plant community as a whole.

Britain's prime minister said Wednesday he will offer citizens a vote on whether to leave the European Union if his party wins the next election, prompting warnings from fellow member states about the soundness of such a move.

Claiming that public disillusionment with the 27-nation EU is "at an all-time high," David Cameron used a long-awaited speech in central London to say that the terms of Britain's membership in the bloc should be revised and the country's citizens should have a say.

Cameron proposed Wednesday that his Conservative Party renegotiate the U.K.'s relationship with the European Union if it wins the next general election, expected in 2015.

"Once that new settlement has been negotiated, we will give the British people a referendum with a very simple in or out choice to stay in the EU on these new terms. Or come out altogether," Cameron said. "It will be an in-out referendum."

My guess is that Britain will stay in, especially since the so-called ' 51st state option' (or hopefully 52nd) has been seriously downplayed by the current administration. Depending on how long the negotiations take for the EU and Britain, the referendum may not take place until the next US presidential administration. That may a change in policy. I have doubts on that, whether the new administration is Republican or Democrat: its too useful to have a strong pro-US voice in the EU.

If the Brits did leave the EU, I have to wonder if that might be the catalyst to cause the Scots to split with the UK and go it alone. *IF* the Brits as a whole left and the Scots seceded, would our special relationship with an EU member shift north to Scotland? Or back to Germany like it was to some extent under Clinton? The latter I suspect. However, I cannot say for certain. I'm a techie with interests in this sort of thing rather than an expert.

Ice cores drilled in the Greenland ice sheet, recounting the history of the last great warming period more than 120,000 years ago, are giving scientists their clearest insight to a world that was warmer than today.

In a paper published today in the journal Nature, scientists have used a 2,540 metre long Greenland ice core to reach back to the Eemian period 115-130 thousand years ago and reconstruct the Greenland temperature and ice sheet extent back through the last interglacial. This period is likely to be comparable in several ways to climatic conditions in the future, especially the mean global surface temperature, but without anthropogenic or human influence on the atmospheric composition.

The Eemian period is referred to as the last interglacial, when warm temperatures continued for several thousand years due mainly to the earth's orbit allowing more energy to be received from the sun. The world today is considered to be in an interglacial period and that has lasted 11,000 years, and called the Holocene.

"The ice is an archive of past climate and analysis of the core is giving us pointers to the future when the world is likely to be warmer," says CSIRO's Dr Mauro Rubino, the Australian scientist working with the North Greenland Eemian ice core research project.

Dr Rubino says the Greenland ice sheet is presently losing mass more quickly than the Antarctic ice sheet. Of particular interest is the extent of the Greenland continental ice sheet at the time of the last interglacial and its contribution to global sea level.

Deciphering the ice core archive proved especially difficult for ice layers formed during the last interglacial because, being close to bedrock, the pressure and friction due to ice movement impacted and re-arranged the ice layering. These deep layers were "re-assembled" in their original formation using careful analysis, particularly of concentrations of trace gases that tie the dating to the more reliable Antarctic ice core records.

Using dating techniques and analysing the water stable isotopes, the scientists estimated the warmest Greenland surface temperatures during the interglacial period about 130,000 years ago were 8±4oC degrees warmer than the average of the last 1,000 years.

At the same time, the thickness of the Greenland ice sheet decreased by 400±250 metres.

"The findings show a modest response of the Greenland ice sheet to the significant warming in the early Eemian and lead to the deduction that Antarctica must have contributed significantly to the 6 metre higher Eemian sea levels".

There is no more iconic image in biology than that of DNA's double-stranded helix, which coils and supercoils on itself to form dense chromosomes.

But a quite different, square-shaped type of DNA structure can easily be created in the laboratory by the folding of synthetic DNA strands rich in guanine, one of the building blocks of DNA. Scientists have long believed that these so-called 'G-quadruplex structures' may occasionally form in the DNA of living cells. A G-quadruplex comprises four guanines from different places along a G-rich strand held together by a special type of hydrogen bonding to form a compact square structure that interrupts the DNA helix.

In a paper published online today in Nature Chemistry, researchers led by Shankar Balasubramanian at the University of Cambridge, UK, provide strong evidence that G-quadruplexes do occur in cells — and that these unusual structures may have important biological functions.

Researchers still have much to learn about the volcanism that shaped our planet's early history. New evidence from a team led by Carnegie's Frances Jenner demonstrates that some of the tectonic processes driving volcanic activity, such as those taking place today, were occurring as early as 3.8 billion years ago. Their work is published in Geology.

Upwelling and melting of the Earth's mantle at mid-ocean ridges, as well as the eruption of new magmas on the seafloor, drive the continual production of the oceanic crust. As the oceanic crust moves away from the mid-ocean ridges and cools it becomes denser than the underlying mantle. Over time the majority of this oceanic crust sinks back into the mantle, which can trigger further volcanic eruptions. This process is known as subduction and it takes place at plate boundaries.

Volcanic eruptions that are triggered by subduction of oceanic crust are chemically distinct from those erupting at mid-ocean ridges and oceanic island chains, such as Hawaii. The differences between the chemistry of magmas produced at each of these tectonic settings provide 'geochemical fingerprints' that can be used to try to identify the types of tectonic activity taking place early in the Earth's history.

Previous geochemical studies have used similarities between modern subduction zone magmas and those erupted about 3.8 billion years ago, during the Eoarchean era, to argue that subduction-style tectonic activity was taking place early in the Earth's history. But no one was able to locate any suites of volcanic rocks with compositions comparable to modern mid-ocean ridge or oceanic island magmas that were older than 3 billion years and were also free from contamination by continental crust.

Because of this missing piece of the puzzle, it has been ambiguous whether the subduction-like compositions of volcanic rocks erupted 3.8 billion years ago really were generated at subduction zones, or whether this magmatism should be attributed to other processes taking place early in the Earth's history. Consequently, evidence for subduction-related tectonics earlier than 3 billion years ago has been highly debated in scientific literature.

Jenner and her team collected 3.8 billion-year-old volcanic rocks from Innersuartuut, an island in southwest Greenland, and found the samples have compositions comparable to modern oceanic islands, such as Hawaii.

Thursday, January 17, 2013

Dunes of exotic, hydrocarbon sand are slowly but steadily filling in [Titan's] craters, according to new research using observations from NASA's Cassini spacecraft.

"Most of the Saturnian satellites – Titan's siblings – have thousands and thousands of craters on their surface. So far on Titan, of the 50 percent of the surface that we've seen in high resolution, we've only found about 60 craters," said Catherine Neish, a Cassini radar team associate based at NASA's Goddard Space Flight Center, Greenbelt, Md. "It's possible that there are many more craters on Titan, but they are not visible from space because they are so eroded. We typically estimate the age of a planet's surface by counting the number of craters on it (more craters means an older surface). But if processes like stream erosion or drifting sand dunes are filling them in, it's possible that the surface is much older that it appears."

"This research is the first quantitative estimate of how much the weather on Titan has modified its surface," adds Neish.

Titan is the only moon in the solar system with a thick atmosphere, and the only world besides Earth known to have lakes and seas on its surface. However, with a frigid surface temperature of around minus 290 degrees Fahrenheit (94 kelvins), the rain that falls from Titan's skies is not water but instead liquid methane and ethane, compounds that are normally gases on Earth.

Neish and her team made the discovery by comparing craters on Titan to craters on Jupiter's moon Ganymede. Ganymede is a giant moon with a water ice crust, similar to Titan, so craters on the two moons should have similar shapes. However, Ganymede has almost no atmosphere and thus no wind or rain to erode its surface.

"We found that craters on Titan were on average hundreds of yards (meters) shallower than similarly sized craters on Ganymede, suggesting that some process on Titan is filling its craters," says Neish, who is lead author of a paper about this research published online in the journal Icarus Dec. 3, 2012.

The team used the average depth-versus-diameter trend for craters on Ganymede derived from stereo images from NASA's Galileo spacecraft. The same trend for craters on Titan was calculated using estimates of the crater depth from data derived from images made by Cassini's radar instrument.

Titan's atmosphere is mostly nitrogen with a trace of methane and other, more complex molecules made of hydrogen and carbon (hydrocarbons). The source of Titan's methane remains a mystery because methane in the atmosphere is broken down over relatively short timescales by sunlight. Fragments of methane molecules then recombine into more complex hydrocarbons in the upper atmosphere, forming a thick, orange smog that hides the surface from view. Some of the larger particles eventually rain out on to the surface, where they appear to get bound together to form the sand.

"Since the sand appears to be produced from the atmospheric methane, Titan must have had methane in its atmosphere for at least several hundred million years in order to fill craters to the levels we are seeing," says Neish. However, researchers estimate Titan's current supply of methane should be broken down by sunlight within tens of millions of years, so Titan either had a lot more methane in the past, or it is being replenished somehow.

Team members say it's possible that other processes could be filling the craters on Titan: erosion from the flow of liquid methane and ethane for example. However, this type of weathering tends to fill a crater quickly at first, then more slowly as the crater rim gets worn down and less steep. If liquid erosion were primarily responsible for the infill, then the team would expect to see a lot of partially filled craters on Titan. "However, this is not the case," says Neish. "Instead we see craters at all stages; some just beginning to be filled in, some halfway, and some that are almost completely full. This suggests a process like windblown sand, which fills craters and other features at a steady rate."

All solid materials under stress flow very slowly over time. This is called viscous flow, and it is like what happens when someone takes a scoop out of a fresh tub of whipped cream -- the material slowly flows in to fill the hole and flatten the surface. Craters on icy satellites tend to get shallower over time as the ice flows viscously, so it's possible that some of the shallow craters on Titan are simply much older or experienced a higher heat flow than the similarly sized, fresh craters on Ganymede studied in this work.

However, Titan's crust is mostly water ice, and at the extremely low temperatures on Titan, ice shouldn't flow enough to account for such a large difference in depth compared to the Ganymede craters, according to the team. Also, just like stream erosion, deformation from viscous flow tends to happen rapidly at first, then more slowly as the material adjusts, so one would expect to see a lot of partially filled craters on Titan if its surface was deforming easily through viscous flow.

As Cassini flies past Titan on its multi-year tour of Saturn and its moons, the radar instrument gradually builds up a map of the surface. To date, the instrument has provided data in strips covering approximately 50 percent of Titan's surface. The craters measured by the team are all within about 30 degrees of the equator, a relatively dry region on Titan.

"However, the presence of liquids on the surface and in the near subsurface can also cause extensive modification to crater shape, as is observed on Earth," says Neish. "In the case of Titan, liquids consist of hydrocarbons, either as wet sediments (such as those observed at the Huygens landing site) or shallow marine environments (such as the lakes observed at the north and south poles). Craters formed in similar environments on Earth lack any significant surface topography, including the absence of a raised rim, as wet sediments slump into the crater. It is possible that the lack of topography associated with marine-target impacts may help to explain the relative scarcity of impact craters observed near the poles of Titan. If Titan's polar regions are saturated by liquid hydrocarbons, craters formed in those regions may lack any recognizable topographic expression."

On November 15-18, 2012, Dr. Ford attended the 4th Xiangshan Forum in Beijing, an event sponsored by the International Military Branch of the China Association for Military Science of the Academy of Military Science of the People’s Liberation Army (PLA). The paper he presented to this conference appears on NPF and on the Hudson Institute website. Below, however, appears a follow-up essay based upon Dr. Ford’s experiences at the conference, where he served on a Roundtable discussion group focused upon strategic mutual trust.

Go read. Its interesting. I am unsure how to interpret this as yet. Perhaps they are just getting into the international order and a bit insecure. That would mean that they will settle into the international order in a manner that will become more relaxed over time as their interests are taken into account and accepted as peers or even leaders in that order. or this could mean a sign of a future up-ending that order (intentionally or not) based on a Sinocentric model. I do not have an answer either way. It will be interesting to watch over the next two decades. Which will it be?

Sea cows (manatees, dugongs) are the only living marine mammals to feed solely on aquatic plants. Unlike whales or dolphins (Cetacea), the earliest evolutionary history of sirenians is poorly documented, and limited to a few fossils including skulls and skeletons of two genera composing the stem family of Prorastomidae (Prorastomus and Pezosiren). Surprisingly, these fossils come from the Eocene of Jamaica, while stem Hyracoidea and Proboscidea - the putative sister-groups to Sirenia - are recorded in Africa as early as the Late Paleocene. So far, the historical biogeography of early Sirenia has remained obscure given this paradox between phylogeny and fossil record. Here we use X-ray microtomography to investigate a newly discovered sirenian petrosal from the Eocene of Tunisia. This fossil represents the oldest occurrence of sirenians in Africa. The morphology of this petrosal is more primitive than the Jamaican prorastomids’ one, which emphasizes the basal position of this new African taxon within the Sirenia clade. This discovery testifies to the great antiquity of Sirenia in Africa, and therefore supports their African origin. While isotopic analyses previously suggested sirenians had adapted directly to the marine environment, new paleoenvironmental evidence suggests that basal-most sea cows were likely restricted to fresh waters.

A perceived recent increase in global jellyfish abundance has been portrayed as a symptom of degraded oceans. This perception is based primarily on a few case studies and anecdotal evidence, but a formal analysis of global temporal trends in jellyfish populations has been missing. Here, we analyze all available long-term datasets on changes in jellyfish abundance across multiple coastal stations, using linear and logistic mixed models and effect-size analysis to show that there is no robust evidence for a global increase in jellyfish. Although there has been a small linear increase in jellyfish since the 1970s, this trend was unsubstantiated by effect-size analysis that showed no difference in the proportion of increasing vs. decreasing jellyfish populations over all time periods examined. Rather, the strongest nonrandom trend indicated jellyfish populations undergo larger, worldwide oscillations with an approximate 20-y periodicity, including a rising phase during the 1990s that contributed to the perception of a global increase in jellyfish abundance. Sustained monitoring is required over the next decade to elucidate with statistical confidence whether the weak increasing linear trend in jellyfish after 1970 is an actual shift in the baseline or part of an oscillation. Irrespective of the nature of increase, given the potential damage posed by jellyfish blooms to fisheries, tourism, and other human industries, our findings foretell recurrent phases of rise and fall in jellyfish populations that society should be prepared to face.

Toxodonts were a group of large-sized notoungulates of South American origin. They were diverse and widespread in South America in deposits ranging in age from late Oligocene to late Pleistocene. Sparse remains have been found from the Pleistocene of isolated regions of Central America. All of the Central American specimens have been referred to the genus Mixotoxodon (Van Frank, 1950). They were not previously known north of the southern Mexican states of Michoacan and Veracruz, except for an unconfirmed report of an occurrence in Tamaulipas (Arroyo-Cabrales et al., 2010). Here we report the occurrence of a single toxodont tooth, a left upper third molar, from late Pleistocene deposits in Harris County, Texas (30◦N). This is the first record of toxodonts, or any notoungulate, in the United States and extends the geographic range of this group
1600 km north of their previously known localities at Hihuitl ´ an, Michoacan (18◦52 30 N, 103◦24 14 W) and La Estribera, Veracruz (18◦07 01.27 N, 94◦53 15.59W) (Polaco et al., 2004) to latitude 30◦N.

Carl Woese died Dec. 30. Woese remains little known, even among non-microbial biologists but particularly among the public. He endured a decade or more of skepticism, ridicule, and ostracism before his observations were accepted and was deeply hurt by the initial reaction [...] In recent years, some — including the editorial board at Nature Reviews Microbiology — pushed for Woese to receive the Nobel prize for his contributions. Now, that will never happen.

But Woese is not the only unsung hero in this story. The organisms he revealed — the archaea — are fascinating and abundant creatures, yet are hardly ever discussed in depth, even within the confines of microbiology classes. That is a shame. Archaea are everywhere — in deep sea vents, in salt flats, in ice, in sea water, in soil, and in you. And they deserve better publicity.

Phylogenetic analysis of a large dataset (72 taxa, 212 characters) focuses on the in-group relationships of temnospondyls, the largest lower tetrapod clade. Representatives of all clades and grades were considered, spanning the entire stratigraphical range of temnospondyls from the Early Carboniferous through to the Early Cretaceous. Several major groups are defined phylogenetically (node or branch-based) rather than by apomorphies. The following groups were unequivocally found to be monophyletic: Edopoidea (node), Dvinosauria (stem, excl. Brachyopidae), Dissorophoidea (node), Eryopidae (stem), and Stereospondyli (node). The latter encompass three well-defined, branch-based taxa: Rhinesuchidae, Trematosauria and Capitosauria. Trematosauria (stem) contain Trematosauroidea (node), which includes the classic trematosaurids, metoposaurids, and possibly part of the rhytidosteids (Peltostega) but their in-group relationships remain unsettled; most other short-snouted stereospondyls (chigutisaurids, brachyopids, Laidleria and the plagiosaurids) are probably monophyletic and likely nest in some form with trematosauroids. Capitosauria (stem) include the Capitosauroidea (node) spanned by Parotosuchus and Mastodonsaurus, with the successive stem taxa Edingerella, Benthosuchus, Wetlugasaurus and Watsonisuchus. In all variant analyses, edopoids form the basalmost temnospondyl clade, followed by a potential clade (or grade) of small terrestrial taxa containing Balanerpeton and Dendrerpeton (‘Dendrerpetontidae’). All taxa higher than Edopoidea are suggested to form the monophyletic stem taxon Eutemnospondyli, tax. nov. The remainder of Temnospondyli fall into four robust and undisputed clades: (1) Dvinosauria; (2) Zatracheidae plus Dissorophoidea; (3) Eryopidae; and (4) Stereospondyli. These taxa are together referred to as Rhachitomi (node). Eryopidae and Stereospondylomorpha are probably monophyletic, here referred to as Eryopiformes (tax. nov.). The position of Dissorophoidea + Zatracheidae is still ambiguous; it may either form the sister taxon of Dvinosauria, or nest between Dvinosauria and Eryopiformes, whereas there is no support for Euskelia (Dissorophoidea + Eryopidae) after basal taxa of each clade are better understood.

Saturday, January 12, 2013

New bones attributed to Homo floresiensis -- aka the "Hobbit Human" -- along with other recent findings, are helping to reveal what members of this species looked like, how they behaved, and their origins.

The latest findings, described in a Journal of Human Evolution paper, are wrist bones unearthed on the Indonesian island of Flores. Since they are nearly identical to other such bones for the Hobbit found at the site, they refute claims that H. floresiensis never existed.

"The tiny people from Flores were not simply diseased modern humans," Caley Orr, lead author of the paper, told Discovery News.

"The new species of human stood approximately 3' 6" tall, giving it its nickname 'The Hobbit,'" continued Orr, who is an assistant professor in the Department of Anatomy at Midwestern University.

He said that they were "similar to modern humans in many respects." For example, he explained that they walked on two legs, had small canine teeth, and lived what appears to have been an iconic "cave man'" lifestyle.

"Stone tools and evidence of fire use were found in the cave, along with the remains of butchered animals, such as Stegodon (an extinct elephant relative), indicating that meat was a part of diet," Orr said.

He and his colleagues, however, also point out the differences between the Hobbit individuals and modern humans.

The Hobbits had arms that were longer than their legs, giving them a slightly more ape-like structure. Their skulls had no bony chins, so their faces had more of an oval shape. Their forehead was sloping. The inferred brain size was tiny, putting them in the IQ range of chimpanzees.

"Remarkably, the feet were also long relative to the legs, as fantasy fans might expect of a Hobbit," he added.

The Hobbit's wrist looked like that of early human relatives, such as Australopithecus, but the key ancestral candidate now is Homo erectus, "Upright Man."

It is possible that a population of H. erectus became stranded on the Indonesian island and dwarfed there over time. Orr said that "sometimes happens to larger animals that adapt to small island environments."

A problem, however, is that H. erectus is somewhat more modern looking than the Hobbit, so researchers are still seeking more clues.

Another question concerns whether or not the Hobbits ever mated with modern humans. There is evidence that happened to Neanderthals, which have left traces of their genome in modern human DNA. So far, however, conditions have not been right to extract DNA from H. floresiensis bones.

Nonetheless, the Hobbit -- which went extinct relatively recently during the Pleistocene -- is now better known due to the new discoveries.

"These fossils provide further, clear evidence that H. floresiensis is in no way a pathological modern human, or that its primitive morphology is related simply to its small body size," said Tracy Kivell, a paleoanthropologist from the Max Planck Institute for Evolutionary Anthropology. "Instead, it is clearly its own, unique and very intriguing species."

According to a report in The Washington Post yesterday, scientists analysing Australian rocks have discovered traces of bacteria that lived a record-breaking 3.5 billion years ago – a billion years after the Earth was formed.

Old Dominion University biogeochemist Nora Noffke said the traces of bacteria were the oldest fossils ever described.

“Those are our oldest ancestors," Dr Noffke told a meeting of the Geological Society of America. The Washington Post that unlike dinosaur bones, the newly identified fossils were not petrified body parts.

They are textures on the surfaces of sandstone thought to be sculpted by once-living organisms, Dr Noffke said.

Similar patterns decorate parts of Tunisia’s coast, created by thick mats of bacteria that trap and glue together sand particles. Sand that is stuck to the land beneath the mats and thus protected from erosion can over time turn into rock that can long outlast the living organisms above it, according to The Washington Post article.

The ancient Pilbara region was once shoreline and rocks made from sediment piled up billions of years ago are now exposed and available for examination.

Maud Walsh, a biogeologist at Louisiana State University in Baton Rouge, told The Washington Post that while there were older rocks on Earth, the Pilbara find was the “best-preserved sedimentary rocks we know of”.

“They are the ones most likely to preserve the really tiny structures and chemicals that provide evidence for life," she said.

Last year scientists published the discovery of 3.4 billion-year-old fossils in the Pilbara’s Strelley Pool.

"It’s not just finding this stuff that’s interesting," Alan Decho, a geobiologist at the University of South Carolina’s Arnold School of Public Health, told The Washington Post. "It’s showing that the life had some organisation to it."

Ridges that crisscross the rocks like strands in a spider web hint that primitive bacteria linked up in sprawling networks. Like their modern counterparts, they may have lived in the equivalent of microbial cities that hosted thousands of kinds of bacteria, each specialised for a different task and communicating with the others via chemical signals.

Wednesday, January 09, 2013

Animals evolved gradually, from the lowly sponge to the menagerie of tentacled, winged and brainy creatures that inhabit Earth today. This idea makes such intuitive sense that biologists are now stunned by genome-sequencing data suggesting that the sponges were preceded by complex marine predators called comb jellies.

Although they are gelatinous like jellyfish, comb jellies form their own phylum, known as ctenophores. Trees of life typically root the comb jellies' lineage between the group containing jellyfish and sea anemones and the one containing animals with heads and rears — which include slugs, flies and humans. Comb jellies paddle through the sea with iridescent cilia and snare prey with sticky tentacles. They are much more complex than sponges — they have nerves, muscles, tissue layers and light sensors, all of which the sponges lack.

“It’s just wild to imagine” that comb jellies evolved before sponges, says Billie Swalla, a developmental biologist at the University of Washington in Seattle and a leading member of the team sequencing the genome of the comb jelly Pleurobrachia bachei. But the team is suggesting just that, in results they presented at the annual meeting of the Society for Integrative and Comparative Biology, held on 3–7 January in San Francisco, California.

Despite comb jellies' complexity, DNA sequences in the Pleurobrachia genome place them at the base of the animal tree of life, announced Swalla's colleague Leonid Moroz, a neurobiologist at the University of Florida in Gainesville. Another team presented results from genome sequencing for the comb jelly Mnemiopsis leidyi, and found that the phylum lands either below, or as close to the base as, sponges on the tree.

“We’ve always thought that predator–prey interactions and sensory adaptations evolved long after the origin of sponges,” Swalla says. “Now we need to imagine early life as a sponge, ctenophore and everything in between.” Because millions of species have gone extinct since animals appeared some 542 million years ago, Swalla says, the ancestor of all animals might look different from modern comb jellies and sponges.

Gene families, cell-signalling networks and patterns of gene expression in comb jellies support ancient origins as well. For example, Moroz and his team found that comb jellies grow their nerves with unique sets of genes. “These are aliens,” Moroz jokes. He suggests that comb jellies might be descendants of Ediacaran organisms, mysterious organisms that appear in the fossil record before animals. Indeed, in 2011, palaeontologists claimed that one of these 580-million-year-old fossils resembled comb jellies1.

Andy Baxevanis, a comparative biologist at the US National Human Genome Research Institute in Bethesda, Maryland, and a leader on the Mnemiopsis genome project, says that comb jellies are the only animals that lack certain genes crucial to producing microRNA — short RNA chains that help to regulate gene expression. Moreover, he points out, sponges and comb jellies lack other gene families that all other animals possess2, 3.

If comb jellies evolved before sponges, the sponges probably lost some of their ancestors' complexity. Alternatively, says Sally Leys, a biologist at the University of Alberta in Edmonton, sponges may have complexity that scientists have yet to appreciate. “A lot of sponges are more exquisite than a lump on a rock,” she says.

This is an incredible conjecture. I'll wait to see if more research backs this up. Extraordinary claims and all that. If so...the world is far, far weirder and the story of the evolution of the animal kingdom is far more complicated than we ever expected.

A quick thought is to look for pseudogenes in sponges that are relics from something basal to a sponge and the ctenophores.

c. Institute for Rock Magnetism, Department of Geology and Geophysics, University of Minnesota, Minneapolis, MN 55455Abstract:

New rock magnetic results (thermal fluctuation tomography, high-resolution first-order reversal curves and low temperature measurements) for samples from the Paleocene–Eocene thermal maximum and carbon isotope excursion in cored sections at Ancora and Wilson Lake on the Atlantic Coastal Plain of New Jersey indicate the presence of predominantly isolated, near-equidimensional single-domain magnetic particles rather than the chain patterns observed in a cultured magnetotactic bacteria sample or magnetofossils in extracts. The various published results can be reconciled with the recognition that chain magnetosomes tend to be preferentially extracted in the magnetic separation process but, as we show, may represent only a small fraction of the overall magnetic assemblage that accounts for the greatly enhanced magnetization of the carbon isotope excursion sediment but whose origin is thus unclear.

It's not exactly icing on a cake, but it could be icing on a lake. A new paper by scientists on NASA's Cassini mission finds that blocks of hydrocarbon ice might decorate the surface of existing lakes and seas of liquid hydrocarbon on Saturn's moon Titan. The presence of ice floes might explain some of the mixed readings Cassini has seen in the reflectivity of the surfaces of lakes on Titan.

"One of the most intriguing questions about these lakes and seas is whether they might host an exotic form of life," said Jonathan Lunine, a paper co-author and Cassini interdisciplinary Titan scientist at Cornell University, Ithaca, N.Y. "And the formation of floating hydrocarbon ice will provide an opportunity for interesting chemistry along the boundary between liquid and solid, a boundary that may have been important in the origin of terrestrial life."

Titan is the only other body besides Earth in our solar system with stable bodies of liquid on its surface. But while our planet's cycle of precipitation and evaporation involves water, Titan's cycle involves hydrocarbons like ethane and methane. Ethane and methane are organic molecules, which scientists think can be building blocks for the more complex chemistry from which life arose. Cassini has seen a vast network of these hydrocarbon seas cover Titan's northern hemisphere, while a more sporadic set of lakes bejewels the southern hemisphere.

Up to this point, Cassini scientists assumed that Titan lakes would not have floating ice, because solid methane is denser than liquid methane and would sink. But the new model considers the interaction between the lakes and the atmosphere, resulting in different mixtures of compositions, pockets of nitrogen gas, and changes in temperature. The result, scientists found, is that winter ice will float in Titan's methane-and-ethane-rich lakes and seas if the temperature is below the freezing point of methane -- minus 297 degrees Fahrenheit (90.4 Kelvins). The scientists realized all the varieties of ice they considered would float if they were composed of at least 5 percent "air," which is an average composition for young sea ice on Earth. ("Air" on Titan has significantly more nitrogen than Earth air and almost no oxygen.)

If the temperature drops by just a few degrees, the ice will sink because of the relative proportions of nitrogen gas in the liquid versus the solid. Temperatures close to the freezing point of methane could lead to both floating and sinking ice - that is, a hydrocarbon ice crust above the liquid and blocks of hydrocarbon ice on the bottom of the lake bed. Scientists haven't entirely figured out what color the ice would be, though they suspect it would be colorless, as it is on Earth, perhaps tinted reddish-brown from Titan's atmosphere.

"We now know it's possible to get methane-and-ethane-rich ice freezing over on Titan in thin blocks that congeal together as it gets colder -- similar to what we see with Arctic sea ice at the onset of winter," said Jason Hofgartner, first author on the paper and a Natural Sciences and Engineering Research Council of Canada scholar at Cornell. "We'll want to take these conditions into consideration if we ever decide to explore the Titan surface some day."

Cassini's radar instrument will be able to test this model by watching what happens to the reflectivity of the surface of these lakes and seas. A hydrocarbon lake warming in the early spring thaw, as the northern lakes of Titan have begun to do, may become more reflective as ice rises to the surface. This would provide a rougher surface quality that reflects more radio energy back to Cassini, making it look brighter. As the weather turns warmer and the ice melts, the lake surface will be pure liquid, and will appear to the Cassini radar to darken.